Roller separator for printers

ABSTRACT

Rollers or drums of a printer may be separated to prevent damage from continued contact, for example, during shipping. In some embodiments, operation of at least one of the rollers or drums during normal printer operation de-activates the separator. For example, the separator may rotate from a first position, in which it maintains a separation, to a second inactive position where the separator allows the two components to contact for a normal operation.

BACKGROUND

This invention relates generally to printers and, specifically, to devices for separating the rollers thereof prior to actual use.

Generally, in electrophotographic printers it is desirable to separate various rollers and drums. For example, some rollers and drums will chemically attack other rollers and drums when maintained in unmoved contact for long periods of time, especially at higher temperature and humidity conditions. This chemical attack may result in defects in a printed page. In other cases, one roller may end up being softer than another roller and may develop flat spots over time.

The time period involved for such damage varies with the chemistry and environment but may sometimes be on the order of six to eight weeks. Frequently, the shipping and shelf life of a product prior to application and use at the end customer exceeds this period. Moreover, the uncontrolled temperatures during shipment can accelerate the chemical reaction.

To avoid these types of problems, electrophotographic products are generally shipped with various rollers separated from each other with customer removable separating devices. Those devices may be made of plastic, paper, or other materials. During the unpacking and set up of the product, the customer is instructed to remove these separating devices and dispose of or recycle them. The product will not function correctly if these devices are not removed.

One place where such a separator may be utilized is between a charge roll and a photoconductor drum. Generally, in use, the charge roll is spring loaded against the photoconductor drum. A removable separating device fits on each end of the charge roll, holding it away from the drum. The two ends of the separator are connected by a handle or strap to make sure that both ends are removed by the customer.

Thus, there is a need for better ways to maintain the separation between various rollers and drums prior to actual use of electrophotographic devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional depiction of one embodiment of an electrophotographic printer;

FIG. 2 is an enlarged, cross-sectional view of one embodiment of the present invention prior to use; and

FIG. 3 is an enlarged, cross-sectional view corresponding to FIG. 2 in the ready to use configuration in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

Referring now to the drawings and, more particularly, to FIG. 1, there is shown one embodiment of an electro-photographic device 10 in which embodiments of the present invention may be applied. Of course the present invention is in no way limited to any specific printer design and may be applicable to a variety of different printer arrangements.

The device 10 includes laser print heads 12, 14, 16, and 18, a black toner cartridge 20, a magenta toner cartridge 22, a cyan toner cartridge 24, a yellow toner cartridge 26, photoconductive drums 28, 30, 32, and 34, an intermediate transfer belt 36, and a controller 37. In one embodiment, the controller may be a combination of application specific integrated circuits, microprocessors, and firmware suited to the tasks of printing documents.

Each of the laser print heads 12, 14, 16, and 18 projects a respective laser beam 38, 40, 42, and 44 off a respective one of the polygonal mirrors 46, 48, 50, and 52. As each of the polygonal mirrors 46, 48, 50, and 52 rotates, it scans a respective one of the reflected beams 38, 40, 42, and 44 in a scan direction, perpendicular to the plane of FIG. 1, across a respective one of the photoconductive drums 28, 30, 32, and 34.

Each of the photoconductive drums 28, 30, 32, and 34 may be negatively charged, for example, to approximately −1000 volts, and is subsequently discharged to a lower level, such as approximately −300 volts, in the areas of the peripheral surface that are impinged by a respective one of the laser beams 38, 40, 42, and 44.

During each scan of a laser beam across the photoconductive drum, each photoconductive drum 28, 30, 32, and 34 is continuously rotated, for example, in a clockwise direction, in a process direction indicated by the arrow 54. The scanning of the laser beams 38, 40, 42, and 44 across the peripheral surface of the photoconductive drums is cyclically repeated, thereby discharging the areas of the peripheral surfaces on which the laser beams impinge.

The toner in each of the toner cartridges 20, 22, 24, and 26 is negatively charged and is transported upon the surface of a developer roll 80 and biased, for example, to approximately −600 volts. Thus, when the toner for the cartridges 20, 22, 24, and 26 is brought into contact with the respective one of the photoconductive drums 28, 30, 32, and 34, the toner is attracted to and adheres to the portions of the peripheral surfaces of the drums that have been discharged to the lower voltage, say −300 volts, by the laser beams.

As the belt 36 rotates in the direction indicated by the arrow 56, the toner from each of the drums 28, 30, 32, and 34 is transferred to the outside surface of the belt 36. As a print medium, such as paper, travels along the path 58, the toner is transferred to the surface of the print medium and nip 62.

Referring to FIG. 2, a fixed roller, such as a photoconductive drum 28, may rotate in the direction R. Prior to application and use, the drum 28 may be held in a separated position from a charge roll 25, for example. A separator 200 is responsible for maintaining the charge roll 25 and the drum 28 in a fixed spacing. While an embodiment is illustrated involving the maintenance of a separation between a fixed roller, such a photoconductive drum, and a spring loaded roller, such as a charge roll 25, other rollers and drums may use separators 200 as well.

The separator 200 may have a closed complex shape, including a first end 204, which rests against the drum 28. The first end 204 may be finger shaped and may be connected to a convex portion 210. The convex portion 210 has a larger radius of curvature than charge roll 25. A second convex portion 212 has a smaller radius of curvature than charge roll 25. The distance from the center of the axle 215 about which the separator rotates to the surface of portion 210 is larger than the radius of charge roll 25, and the distance from the center of the axle 215 to the surface of portion 212 is smaller than the radius of charge roll 25.

A handle 206 couples the portions 204 and 212. The handle 206 includes an upstanding section coupled to a U-shaped portion 214 which journals the axle 215 of the charge roll 25 in one embodiment.

In use, the spring 208 biases the charge roll 25 against the photoconductive drum 28. Prior to use, for example during shipping, the drum 28 and the roll 25 may be separated by the separator 200. The separation is achieved by the larger radius of the portion 210, held in position by the finger-shaped first end 204.

When the printer is operated, the photoconductive drum 28 rotates in the direction of the arrow R. This rotation of the drum 28 causes clockwise rotation of the separator 200 to the position shown in FIG. 3. In other words, the rotation of the drum 28 causes the portion 210 to act like a roller and to rotate approximately 90° to the position shown in FIG. 3.

The rotation of the separator 200 ends when the portion 212 is juxtaposed from the drum 28. Due to its smaller radius of curvature, the portion 212 ends up being spaced away from the drum 28. The rotation of the separator 200 in the direction indicated by the arrow S is arrested by the stop 202. In this position, a spring 208 presses the charge roll 25 against the drum 28.

In some embodiments, the separation is automatically eliminated at the right time—the time when the printer is being operated. As a result, there is no need for the user to be forced to remember to remove, not only one separator, but both separators between each pair of separated components.

While it typically may not be necessary, if for any reason it is thereafter desired to re-separate the drum 28 and roll 25, all that needs to be done is to rotate the handle portion 206 back to the position shown in FIG. 2, immediately reestablishing the desired separation. For example, this re-separation may be done before shipment or storage.

In some embodiments of the present invention, a separator may be less expensive than conventional separators. Moreover, the separator may be easily snapped onto the shaft of the moveable roller. Also, in some cases, no customer action or intervention is required. Likewise, nothing need be discarded and the separator is available for future use if ever needed. In some embodiments, the friction between the U-shaped portion 214 of the separator 200 and the axle 215 of the spring loaded roll 25 may be sufficient to maintain the separator in the position shown in FIG. 3 without moving, rattling, or shaking.

In some embodiments, two separators can be used on each of two opposed ends of two rollers or drums to be separated.

References throughout this specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation encompassed within the present invention. Thus, appearances of the phrase “one embodiment” or “in an embodiment” are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be instituted in other suitable forms other than the particular embodiment illustrated and all such forms may be encompassed within the claims of the present application.

While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention. 

1. A method comprising: separating two printer elements prior to operation of the printer; and automatically contacting said elements in response to printer operation.
 2. The method of claim 1 including using a separator to separate first and second printer elements, said separator including a first section to engage said first printer element and a second section to disengage said first printer element, a distance from the center of an axle of a second printer element to the first section is greater than the radius of the second printer element and a distance from the center of the axle to the second section is less than the radius of the first printer element.
 3. The method of claim 2 including providing a handle on said separator.
 4. The method of claim 2 including providing a finger-shaped protrusion to arrest the rotation of said separator.
 5. The method of claim 1 including providing a separator which is mounted on the axle of one of said elements and which engages the other of said elements to maintain a separation between said elements.
 6. The method of claim 1 including separating a fixed roller and a movable roller.
 7. The method of claim 6 including separating a photoconductive drum from a roller.
 8. The method of claim 7 including separating a photoconductive drum from a charge roll.
 9. The method of claim 1 including providing a separator which is movable between an active separating orientation and a de-active non-separating orientation.
 10. The method of claim 9 including providing a separator which is rotatable between said orientations.
 11. A separator for a printer comprising: a first portion mountable on an axle of a first rotatable printer element; a second portion to abut against the surface of a second rotatable printer element, said second portion including a first section and a second section, a distance from the center of an axle of a first printer element to the first section is greater than the radius of the first printer element and a distance from the center of the axle to the second section is less than the radius of the first printer element, enabling said separator to rotate around said axle when the printer element, abutted against said second portion, rotates, to remove the separation between said elements.
 12. The separator of claim 11 including a finger-shaped portion coupled to said first portion and forming a free end of said separator.
 13. The separator of claim 12 including a handle coupled to said separator.
 14. The separator of claim 11 wherein said separator is rotatable between a first position separating the printer elements and a second position allowing the printer elements to contact.
 15. A printer comprising: a fixed roller; a movable roller; and a separator between said fixed and movable rollers to separate said fixed roller from said movable roller prior to operation of said printer, and upon operation of the printer to automatically allow said rollers to contact each other.
 16. The printer of claim 15 wherein said separator to rotate from a first orientation, separating said rollers, to a second orientation in response to operation of at least one of said rollers.
 17. The printer of claim 15 wherein said fixed roller is a photoconductive drum.
 18. The printer of claim 17 wherein said movable roller is a charge roll.
 19. The printer of claim 15 wherein said printer is an electrophotographic printer.
 20. The printer of claim 15 wherein one of said rollers includes an axle, said separator to rotatably mount on said axle to rotate between a first position maintaining the separation between said rollers and a second position allowing said rollers to contact. 